Brake devices for braking vehicles, such as railway vehicles, by using fluid pressure such as hydraulic pressure, pneumatic pressure, and the like, have been used conventionally. JP2009-162243A discloses a caliper brake device that brakes rotation of a wheel by friction force between a disk and a pair of brake shoes, by clamping the disk, rotating with the wheel, by the pair of brake shoes. With this caliper brake device, sliding of a pressing piston, relative to a cylinder, is made by compressed air guided to a pressure chamber, so as to press the brake shoes against the disk.